Organic Electronic Component with Dopant, Use of a Dopant and Method for the Production of the Dopant

ABSTRACT

An organic electronic component with a dopant, a method for using a dopant and a method for producing a dopant are disclosed. In an embodiment the component includes a substrate and a first electrode arranged on the substrate. The component further includes at least one organic functional layer arranged on the first electrode, the at least one organic functional layer including a matrix material into which a p-dopant has been introduced and a second electrode arranged on the at least one organic functional layer, wherein the p-dopant includes a copper complex having at least one ligand, wherein the ligand has a benzene unit with two carbon atoms, wherein each carbon atom of the benzene unit has an aryloxy group and an iminium group directly attached as substituents, and wherein the at least one organic functional layer is hole-conducting.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. application Ser. No.14/352,292, filed on Apr. 16, 2014 and issued as U.S. Pat. No. 9,799,840on Oct. 24, 2017 which is a national phase filing under section 371 ofPCT/EP2012/070537, filed Oct. 17, 2012, which claims the priority ofGerman patent application 10 2011 084 639.5, filed Oct. 17, 2011, eachof which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

An organic electronic component comprising a dopant is specified, as area use of a dopant and a process for producing a dopant.

BACKGROUND

Factors that influence efficiency and lifetime of organic electroniccomponents, for example, organic light-emitting diodes, include thequality of the charge carrier injection and the charge carriertransport. By means of doping, the conductivity of materials, and hencethe charge carrier transport, can be increased by several orders ofmagnitude. The doping of organic materials with electron acceptors can,for example, increase the conductivity of hole conductor layers.

SUMMARY

One embodiment provides an organic electronic component having a noveldopant. A further embodiment provides a use of a novel dopant in a holetransport material. A further embodiment provides a process forproducing a dopant.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is to be illustrated in detail by the figures and workingexamples. In the figures, identical elements are indicated by identicalreference numerals. The figures should not be regarded as scaledrawings.

FIG. 1a shows the schematic three-dimensional view of an organiclight-emitting diode;

FIG. 1b shows the schematic side view of an organic light-emittingdiode;

FIG. 2 shows the IV characteristics of doped hole transport layers in afirst embodiment;

FIG. 3 shows conductivities of doped hole transport layers in a firstembodiment as a function of the dopant concentration;

FIG. 4 shows absorption spectra of the doped hole transport layers inthe first embodiment;

FIG. 5 shows photoluminescence spectra of the doped hole transportlayers in the first embodiment;

FIG. 6 shows reflection spectra of the doped hole transport layers inthe first embodiment;

FIG. 7 shows IV characteristics of doped hole transport layers in asecond embodiment;

FIG. 8 shows conductivities of a second embodiment of doped holetransport layers as a function of the dopant concentration;

FIG. 9 shows absorption spectra of the doped hole transport layers inthe second embodiment;

FIG. 10 shows photoluminescence spectra of the doped hole transportlayers in the first embodiment; and

FIG. 11 shows reflection spectra of the doped hole transport layers inthe first embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

An organic electronic component is described, comprising a substrate, afirst electrode on the substrate, at least one organic functional layercomprising a matrix material into which a p-dopant has been introducedon the first electrode, and a second electrode on the at least oneorganic functional layer. This p-dopant comprises a copper complexhaving at least one ligand containing an aryloxy group and an iminiumgroup.

“p-Dopant” in this context is understood to mean a dopant havingelectron acceptor properties, which can thus generate especially holes,i.e., positive charge carriers or missing electrons, for example, in amatrix material into which it may be embedded. The dopant increases thenumber of free charge carriers and hence the conductivity, which is aproduct of mobility and number of charge carriers. Assuming that themobility stays the same, there is an increase in the conductivity ondoping through the increase in the number of charge carriers.

“On” in connection with the arrangement of the elements of the componentmay be understood to mean either a direct arrangement or an indirectarrangement. Thus, two elements may be arranged one on top of anothersuch that they encompass a common interface, or such that furtherelements are arranged between them.

“Copper complex” hereinafter shall be understood to mean anorganometallic complex which contains a copper cation as the centralatom, and at least one ligand. More particularly, the copper complex mayhave two ligands. The aryloxy group of the at least one ligand may becoordinated or bound to the copper cation by the oxygen atom presenttherein, and the iminium group by the nitrogen atom present therein. Iftwo ligands are present in the copper complex, the copper cation maythus be coordinated or bound to two oxygen atoms and to two nitrogenatoms.

Such a component has a functional layer with optimized hole transportand, compared to the rest of the component, a minimized voltage drop andhence improved efficiency.

If the organic electronic component is an organic light-emitting diode,the p-dopant in the at least one functional layer may additionallyinfluence the appearance of the light-emitting diode in the switched-offstate (called the “off-state appearance”). The p-dopant is configuredsuch that the color of the functional layer into which it has beenintroduced can be modified as a function of the concentration of thep-dopant without altering the electrical conductivity of the functionallayer.

To date, organic light-emitting diodes have been configured in such away that, for example, reddish hole conductor layers which absorb someblue and some green light are optically compensated such that the diodesin the switched-on state emit a pleasant white light. With the novelp-dopant, the light-emitting diode, even in the switched-off state, canbe given a visual color impression when the functional layer, forexample, adjoins a transparent electrode.

In one development, the aryloxy group and the iminium group of theligand are a salicylaldiminate group. “Salicylaldiminate group” isunderstood to mean a ligand formed from a salicylaldehyde and anaromatic mono- or diamine or an olefinic mono- or diamine. Thus, theligand comprises an amine-fused salicylaldehyde group and is capable ofcomplexation between aryloxy group and the nitrogen of the iminiumgroup, for example an azomethine group. Thus, p-dopants reduced in costcompared to p-dopants used to date are provided.

If the copper complex has two ligands of this kind, because of theirstructure, these may be coordinated to the copper cation such that thecopper complex has a cis structure or a trans structure. The coppercomplex having cis structure can be converted to a copper complex havingtrans structure. By means of temperature, pressure and choice ofsolvent, the synthesis of the copper complex can be controlled such thatone isomer, cis or trans structure, forms preferentially.

In addition, the copper cation in the copper complex may be present inthe II oxidation state. The notation Cu^(II) is therefore also usedhereinafter.

In a further embodiment, the copper complex may have one of the generalformulae I or II:

Formula (I) is a cis isomer of the copper complex, formula (II) a transisomer. Such a copper complex thus contains two ligands coordinated orbound to the copper cation.

In the formulae (I) and (II): R₁, R_(1′), R_(2x) and R_(2x′) (where eachx represents a, b, c or d) are each independently selected from a groupcomprising unbranched, branched, fused, cyclic, unsubstituted andsubstituted alkyl radicals, substituted and unsubstituted aromatics,substituted and unsubstituted heteroaromatics.

Examples of such substituents are methyl groups, ethyl groups,decahydronaphthyl groups, cyclohexyl groups and alkyl radicals which ormay be partly substituted and have up to 20 carbon atoms. These alkylradicals may additionally contain ether groups such as ethoxy or methoxygroups, ester groups, amide groups, carbonate groups or else halogens,especially F.

Examples of substituted or unsubstituted aromatics are phenyl, diphenyl,naphthyl, phenanthryl or benzyl.

Examples of possible heteroatoms are shown in table 1 below. For thesake of simplicity, only the base structure of each of theheteroaromatics is shown. In principle, this base structure may besubstituted by further R radicals which may be of a form analogous tothe above-defined R₁, R_(1′), R_(2x) and R_(2x′) radicals. The bond tothe ligand may be at any bonding-capable site in the base structure.

TABLE 1

In addition, the substituents in the general formulae (I) and (II) inthe two ligands may be the same or different. In one embodiment, R₁ andR_(1′) and R_(2x) and R_(2x′) are each the same. If the substituentsselected are the same, the synthesis of the copper complex isparticularly simple to conduct, which also causes a reduction in costs.

In addition, R₁ and R_(1′) may be joined to one another. Thus, a bridgemay be formed between the two ligands coordinated or bound to the coppercation. Embodiments of this kind are shown in the general forms (Ia) and(IIa).

Formulae (Ia) and (IIa) are each cis isomers of the bridged coppercomplex. In principle, a bridge is also conceivable in trans isomerswhen an appropriately long bridge between R₁ and R_(1′) is selected. Forthe R₃, R_(3′), R₄ and R_(4′) radicals, the definitions of the R₁,R_(1′), R₂ and R_(2′) radicals apply correspondingly.

Copper complexes having one of these general formulae (I), (Ia), (II) or(IIa), because of their Lewis acidity, can be used effectively asp-dopants, since they have electron-withdrawing ligands and hence theirelectron acceptor properties are enhanced. Thus, the hole conductivityin the organic functional layer of the organic electronic component isimproved.

In a further embodiment, at least one of R₁, R_(1′), R_(2x) and R_(2x′)and—if present—of R₃, R_(3′), R₄ and R_(4′) may have anelectron-withdrawing substituent.

An electron-withdrawing substituent, for example, a fluorine atom F, maybe present directly at the bonding carbon of at least one of the R₁,R_(1′), R_(2x) and R_(2x′) radicals and—if present—of R₃, R_(3′), R₄ andR_(4′). Such a radical may have, for example, one of the generalformulae (IIIa) or (IIIb):

In the formula (IIIa), n may be 1 to 20, R₁₀ may be a fluorine atom F.In one variant, n=2 and R₁₀═F. R₁₀ may also be selected in the same wayas the R₁, R_(2x), R₃ and R₄ radicals. Particular preference is givenhere to aliphatic chains and aromatics.

In formula (IIIb), n, m and o may each independently be 0 to 20; moreparticularly, n and m may be 2 and o may be selected within the rangefrom 1 to 5. R₁₀ may be F and B may be O. Alternatively, B may also beselected from S, Se, NH, N—R, PH and P—R, where R may be selected as perR₁, R_(2x), R₃ and R₄. Otherwise, R₁₀ may be selected in the same way asthe R₁, R_(2x), R₃ and R₄ radicals. Particular preference is given hereto aliphatic chains and aromatics.

In addition, an electron-withdrawing substituent may also be present onan aromatic R₁, R_(2x), R₃ or R₄ radical. Examples of such radicals areshown in the general formulae (IIIc) and (IIId):

In the formulae (IIIc) and (IIId), R₁₁ to R₁₇ may each independently beselected from a group comprising H, F, CF₃, CN and NO₂. In addition, R₁₁to R₁₇ may each independently be selected in the same way as the R₁,R_(2x), R₃ and R₄ radicals. More particularly, they may comprise whollyor partly fluorinated systems.

Electron-withdrawing substituents in the R₁, R_(2x), and—if present—R₃and R₄ radicals may further enhance the hole-conducting character of theradicals, since they increase the electron-withdrawing action of theligand, such that p-dopants having electron-withdrawing substituents inthe ligands are particularly effective in increasing the electricalconductivity of the functional layer into which they have beenintroduced.

The at least one organic functional layer may be hole-conducting. Forexample, it may be a hole transport layer or a hole injection layer.

The matrix material of the functional layer may be a hole transportmaterial comprising organic small molecules, polymers or mixturesthereof.

If the hole transport layer is selected from small molecules, these maybe selected, for example, from a group comprisingN,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-9,9-dimethylfluorene,N,N′-bis(3-methyl-phenyl)-N,N′-bis(phenyl)-9,9-diphenylfluorene,N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-9,9-diphenyl-fluorene,N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-2,2-dimethylbenzidine,N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)-9,9-spirobifluorene,2,2′,7,7′-tetrakis-(N,N-diphenylamino)-9,9′-spirobifluorene,N,N′-bis-(naphthalen-1-yl)-N,N′-bis(phenyebenzidine,N,N′-bis-(naphthalen-2-yl)-N,N′-bis(phenyl)benzidine,N,N′-bis-(3-methylphenyl)-N,N′-bis(phenyl)benzidine,N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)-9,9-dimethylfluorene,N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-9,9-spirobifluorene,di-[₄-(N,N-ditolylamino)phenyl]cyclo-hexane,2,2′,7,7′-tetra(N,N-ditolyl)aminospirobi-fluorene,9,9-bis[4-(N,N-bisbiphenyl-4-ylamino)-phenyl]-9H-fluorene,2,2′,7,7′-tetrakis[N-naphthalenyl-(phenyl)amino]-9,9-spirobifluorene,2,7-bis[N,N-bis-(9,9-spirobifluoren-2-yl)amino]-9,9-spirobifluorene,2,2′-bis[N,N-bis(biphenyl-4-yl)amino]-9,9-spirobi-fluorene,N,N′-bis(phenanthren-9-yl)-N,N′-bis(phenyl)-benzidine,N,N,N′,N′-tetranaphthalen-2-ylbenzidine,2,2′-bis(N,N-diphenylamino)-9,9-spirobifluorene,9,9-bis[4-(N,N-bis(naphthalen-2-yl)amino)phenyl]-9H-fluorene,9,9-bis[4-(N,N′-bis(naphthalen-2-yl)-N,N′-bisphenylamino)phenyl]-9H-fluorene,titanium oxide phthalocyanine, copper phthalocyanine,2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane,4,4′,4″-tris(N-3-methylphenyl-N-phenylamino)triphenylamine,4,4′,4″-tris(N-(2-naphthyl)-N-phenylamino)triphenyl-amine,4,4′,4″-tris(N-(1-naphthyl)-N-phenylamino)tri-phenylamine,4,4′,4″-tris(N,N-diphenylamino)triphenyl-amine,N,N′-di[(1-naphthyl)-N,N′-diphenyl]-1,1′-biphenyl)-4,4′-diamine,pyrazino[2,3-f][1,10]-phenanthroline-2,3-dicarbonitrile,N,N,N′,N′-tetrakis-(4-methoxyphenyebenzidine,2,7-bis[N,N-bis(4-methoxy-phenyl)amino]-9,9-spirobifluorene,2,2′-bis[N,N-bis(4-methoxyphenyl)amino]-9,9-spirobifluorene,N,N′-di-(naphthalen-2-yl)-N,N′-diphenylbenzene-1,4-diamine,N,N′-diphenyl-N,N′-di[₄-(N,N-ditolylamino)phenyl]-benzidineand N,N′-diphenyl-N,N′-di[4-(N,N-diphenyl-amino)phenyl]benzidine.

Polymeric hole transport materials may be selected from a groupcomprising PEDOT (poly(3,4-ethylene-dioxythiophene), PVK(poly(9-vinylcarbazole), PTPD(poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine), P3HT(poly(3-hexylthiophene) and PANI (polyaniline). These repeat units ofthese illustrative polymeric materials are shown in the formulae (IVa)to (IVe):

If a mixture of small molecules and polymeric hole transport materialsis present, the mixing ratio may be between 0 and 100%.

The abovementioned p-dopants may be present in the matrix material witha concentration of 0.1 to 50% by volume, especially with a concentrationof 2 to 30% by volume.

If an organic functional layer, for example, a hole transport layer, isproduced, the materials, i.e., the matrix material in which the p-dopanthas been embedded, may be deposited from the gas phase or from theliquid phase. If the matrix material contains small molecules, thedeposition can be effected from the liquid phase or from the gas phase;if polymeric materials are selected, these can be deposited from theliquid phase. The film-forming properties in the production of thefunctional layer can be improved in the case of processing from theliquid phase when a mixture of small molecules and polymeric materialsis used as the matrix material.

The solvents used for the deposition from the liquid phase may beorganic solvents selected, for example, from a group comprisingchlorobenzene, chloroform, toluene, THF and methoxypropyl acetate.

In one embodiment, molecules of the p-dopant may be coordinated by atleast one molecule each of the matrix material. For example, the dopingof the matrix material can be effected by virtue of coordination of oneto two hole transport material molecules in the axial positions of thecopper complex. The square-planar coordination environment of the dopantcan thus be expanded through a tetragonal pyramid (one matrix materialmolecule) to an octahedron (two matrix material molecules). Inprinciple, it is also possible that two dopant molecules are bridged viaone bifunctional matrix material molecule.

Using the example of NPB(N,N′-di[(1-naphthyl)-N,N′-diphenyl]-1,1′-biphenyl)-4,4′-diamine) asmatrix material and a schematic copper complex in which only the twobonds from the copper cation to the ligands are shown in each case, sucha coordination is shown in scheme 1:

The coordination is effected via an interaction between the nitrogenatom of the NPB and the copper cation, such that a positive charge onthe copper cation can be delocalized. This delocalization, which canalso extend to other hole-transporting molecules, is shown by the fourillustrative mesomeric structures in scheme 1, but these should beunderstood merely in a formal sense.

The component according to the above details may be selected from agroup comprising field-effect transistors, solar cells, photodetectors,optoelectronic components, light-emitting diodes and displays. Moreparticularly, the component may be an organic light emitting diode(OLED). The functional layer may, especially in OLEDs, take the form ofa hole transport layer which may be arranged close to an electrode, forexample, the anode, and/or of a hole-conducting partial layer of acharge-generating layer sequence (charge generation layer, CGL).

A charge-generating layer sequence may be understood to mean acombination of adjacent n- and p-doped organic partial layers. By meansof a charge-generating layer sequence, it is possible to connectmutually adjacent organic functional stacks to one another, each ofwhich may contain, for example, functional layers and emitting layers,in which case the charge-generating layer sequence can inject chargecarriers into the adjacent organic functional stacks.

By virtue of the components comprising a p-dopant according to the abovedetails, they are less expensive to produce and have optimized chargetransport. Overall, the component can thus have improved efficiency andlifetime. In the case of OLEDs, it is additionally possible to modifythe appearance in the switched-off state through the use of thep-dopant, such that the OLED no longer has a gray appearance, as isconventional, but gives a colored impression to an outside observer.

Additionally specified is the use of a copper complex having at leastone ligand containing an aryloxy group and an iminium group as ap-dopant in a hole transport material. More particularly, the coppercomplex may have one of the general formulae I and II:

whereR₁, R_(1′), R_(2x), R_(2x′) where x=a, b, c or d are each independentlyselected from a group comprising unbranched, branched, fused, cyclic,unsubstituted and substituted alkyl radicals, substituted andunsubstituted aromatics, substituted and unsubstituted heteroaromatics.

In further embodiments, the copper complex may be configured analogouslyto the details given in relation to the p-dopant present in the organicelectronic component. The hole transport materials selected, in whichthe p-dopant is used, may, for example, be the hole transport materialsmentioned in relation to the organic electronic component.

The use of such a copper complex as p-dopant in hole transport materialsincreases the conductivity thereof by multiple orders of magnitude. Thisis brought about at least partly by the Lewis acid properties thereof.In addition, the use of such a copper complex as p-dopant isparticularly inexpensive, since the copper complex can be produced frominexpensive starting materials and by means of a process which is simpleto conduct.

Additionally specified is a process for producing a p-dopant comprisinga copper complex having at least one ligand containing an aryloxy groupand an iminium group, in which the at least one ligand is synthesizedand, at the same time, a copper cation is complexed. Such a process isfirstly inexpensive because of the starting materials used and issecondly particularly simple to conduct.

The simultaneous synthesis of the ligand and of the complex can also bereferred to as a template synthesis, which means that only a one-stagereaction has to be conducted in order to prepare ligand and the complexwith the ligand. The same also applies to the preparation of coppercomplexes having more than one ligand.

In one embodiment of the process, a fluorinated or unfluorinatedsalicylaldehyde and a fluorinated or unfluorinated amine selected from agroup comprising aromatic monoamines, olefinic monoamines, aromaticdiamines and olefinic diamines is reacted with a copper salt. Moreparticularly, a copper(II) salt can be used. Examples of copper(II)salts are CuCl₂, CuBr₂ or copper acetate. For purification, thecompounds obtained can be sublimed.

Scheme 2 shows an embodiment of the process in which salicylaldehyde isreacted with an olefinic diamine and a copper salt to give a coppercomplex wherein the two ligands are bridged (route 1, above the reactionarrow) and with an olefinic monoamine and a copper salt to give a coppercomplex having two unbridged ligands (route 2, below the reactionarrow):

R and R¹ may be selected analogously to the R₁, R_(2x) and, if present,R₃ and R₄ radicals specified above in relation to the p-dopant of theorganic electronic component. The products obtained by route 1 and route2 are indicated by A. Cu^(II)X₂ represents a copper salt which may beselected, for example, from CuCl₂, CuBr₂ and copper acetate.

The reaction proceeds spontaneously and is therefore easy to conduct.

FIGS. 1a ) and 1 b) show a schematic three-dimensional and a schematictwo-dimensional side view of an OLED. A first electrode 20 has beenapplied to a substrate 10. FIG. 1a ) indicates that this electrode maybe structured. A hole injection layer 30 has been applied to the firstelectrode 20, and to the former a hole transport layer 40, an emissionlayer 50, which may comprise a host material and an emission material, ahole-blocking layer 60, an electron transport layer 70 and an electroninjection layer 80. Finally, a second electrode 90, configured as acathode in this example, has been applied. For the sake of clarity, FIG.1a ) does not show all the layers. An OLED need not contain all thelayers between the first and second electrodes 20, 90. In addition,OLEDs according to FIGS. 1a ) and 1 b) may be stacked and be connectedto one another via charge-generating layer sequences (not shown here).

FIG. 1b ) additionally shows that a voltage is applied between the firstelectrode 20 and second electrode 90. This leads to generation ofexcitons and hence to emission of electromagnetic radiation, especiallywithin the visible wavelength range. The arrow in FIG. 1b ) indicatesthe direction in which the radiation is emitted from the component. Inthis case, the radiation is emitted through the substrate 10.Through-emission from the second electrode 90 is likewise conceivable.It is also possible to achieve double-sided emission.

Illustrative materials for the layers shown in FIGS. 1a ) and 1 b)include glass for the substrate 10, ITO (indium tin oxide) or siliconfor the first electrode 20, and aluminum for the second electrode 90.Further materials which can be used in the layers of an OLED are knownto those skilled in the art and will therefore not be elucidated anyfurther here.

Some working examples for syntheses of inventive copper complexes arespecified hereinafter:

1) Copper(II)(N,N′-2,3-butene-1,4-dinitrile-2,3-diyl)-disalicylaldiminate (referredto hereinafter as K1)

A mixture of Cu(CH₃COO)₂ (0.04 mol; 7.99 g) and ethanol (300 ml) isinitially charged and stirred while heating until all of the Cu(CH₃COO)₂has dissolved. In a 2nd reaction mixture, the substances salicylaldehyde(0.021 mol; 2.63 g), diaminomaleonitrile (0.04 mol; 4.32 g) and ethanol(150 ml) are initially charged and likewise dissolved. After the twosolutions have been combined and refluxed overnight, a reddish-blacksolid separates out, which is filtered off (crude product yield: 5.65 g,corresponding to 38%). The crude product is purified byrecrystallization with DMF (300 ml) and subsequent precipitation withethanol/diethyl ether.

The pure substance thus obtained is recrystallized once again with EtOH,dried and sublimed at 220° C. (10⁻⁵ mbar).

2) Copper(II)-(bis-N,N′-4-tolyl)disalicylaldiminate (referred tohereinafter as K2)

Cu(CH₃COO)₂ (0.0233 mol; 4.66 g) is dissolved in ethanol (120 ml). As aseparate solution, p-toluidine (0.047 mol; 5 g) and salicylaldehyde(0.047 mol; 5.7 g) and ethanol (120 ml) are initially charged anddissolved. The two mixtures are combined and stirred at room temperatureovernight. The suspension is concentrated a little and then thebrown-black precipitate is filtered off and dried. The yield of crudeproduct is 9.95 g (corresponding to 87.5%).

The substance (m.p. 205° C.) is sublimed at 180° C. (10⁻⁵ mbar) and thenonce again at 170° C. (10⁻⁵ mbar).

3) Copper(II)-bis(N,N′-4-butyl)disalicylaldiminate (K3 hereinafter)

Salicylaldehyde (S) and butylamine (B) condense in the presence of thecopper salt in ethanolic solution without protic catalysis to give thealdimine derivative which, after formation, is introduced immediatelyinto the ligand sphere of the copper:

K3 has a melting point of 79° C. and sublimes at 79° C. to 81° C. Theyield is 19.8 g (corresponding to 70%).

The working examples which follow show various electrical and opticalproperties of the p-dopants K1 to K3.

4) A 200 nm-thick layer of the hole conductor 1-TNATA(4,4′,4″-tris(N-(1-napthyl)-N-phenylamino)triphenyl-amine) is depositedonto an ITO electrode 20 by thermal vaporization (comparative exampleM1). A150 nm-thick aluminum layer serves as the counter electrode 90. Inthree further experiments, the dopant K1 is introduced by doping inconcentrations of 2% (K1-2), 5% (K1-5) and 10% (K1-10) relative to thevaporization rate in 1-TNATA, the matrix material.

A component of size 4 mm² gives the respective current-voltagecharacteristics (IV characteristics) shown in FIG. 2. The current I in[mA/cm²] is plotted against the voltage U in [V]. The component withconcentration 2% gave the characteristic labeled K1-2, the componentwith concentration 5% the characteristic marked K1-5, and the componentwith concentration 10% the characteristic labeled K1-10. For comparison,the IV characteristic of the pure matrix material is shown, labeled M1.

For all concentrations, it is possible to show that the doping has aneffect on the IV characteristic. For all 3 concentrations, a rise in thecurrent densities is found compared to the comparative example M1. Inthis context, it is additionally found that the doping effect depends onthe dopant concentration and attains the highest current density atconcentration 5%. No ideal symmetric behavior of the characteristic isobserved, but an increase in the current density by a few orders ofmagnitude is achieved even in the negative voltage range, which showsthat injection of holes from the aluminum cathode 90 is also possible.

5) Conductive substrates are coated with the doped materials (M1, K1-2,K1-5 and K1-10) mentioned in example 4. These conductivity substrateswere used to produce a total of 9 components of various dimensions. Forthe determination of conductivity, this rules out any dependence of theeffects measured on the thickness and area of the components. For thissubstrate type, it is not necessary to apply an aluminumcounterelectrode.

The components thus produced give rise to the conductivity of the layerhaving the following specific values for the dopant concentrationsselected here:

M1: 9.10e−9 S/m

K1-2: 1.81e−6 S/m

K1-5: 1.86e−6 S/m

K1-10: 2.15e−6 S/m.

FIG. 3 shows the measured conductivities L in [S/m] against the dopantconcentration C in [% by volume]. At the same time, the profile shownalso confirms the characteristics shown in FIG. 2. The conductivityattains its maximum at concentration 5%, the measured conductivities of2% to 10% having very similar and almost constant conductivities. For apossible application, this gives rise to a relatively large processingwindow for the dopant concentration, without influencing the electricalconductivity thereof.

6) The materials produced in example 4 (M1, K1-2, K1-5 and K1-10) areeach deposited on a quartz glass sheet. These samples do not have anyelectrical contacts and serve merely for measurement of absorption,emission and reflection spectra of the individual layers.

The absorption spectra according to FIG. 4 (the absorption A in [a.u.]is plotted here against the wavelength λ in [nm]) show that the absoluteabsorption at the absorption maximum at wavelength 340 nm drops in thecase of the doped samples compared to the undoped comparative exampleM1. The absolute drop here for K1-2 and K1-10 is at about the samelevel, while the drop at dopant concentration 5% (K1-5) is smaller.

The absorption of the matrix material 1-TNATA below 400 nm is thuslowered by the forming of the doped layer and the associated formationof a charge-transfer complex.

At the same time, however, there is a rise in the absorption between 440nm and 600 nm. This likewise shows the formation of a charge-transfercomplex and successful doping. At the same time, it is additionallyfound that the rise in absorption in this region increases with risingdopant concentration. The absorption spectrum therefore fits very wellwith the results of the conductivity measurements and the IVcharacteristics, which are shown in FIGS. 3 and 2.

For the visible wavelength range from 400 to 700 nm, the absorption inthe blue to green wavelength range thus rises, as a result of which thelayers doped with the p-dopant appear reddish to the human eye.

FIG. 5 shows the photoluminescence (PL) spectra of the abovementionedsamples. The normalized emission E_(n) is plotted against the wavelengthλ in [nm].

The comparison of the PL spectra of undoped 1-TNATA (M1) and K1-doped1-TNATA (K1-2, K1-5, K1-10) shows that the emission at a wavelength of487 nm customary for 1-TNATA moves through 477 nm for dopantconcentration 2% to 463 nm for dopant concentrations 5% and 10%. Thebasic emission profile is maintained, with a decrease in the absoluteemission of 1-TNATA when doped with K1.

The reflection spectra in FIG. 6, in which the reflection R is plottedagainst the wavelength λ in [nm], likewise show the information alreadyshown by the absorption spectrum in FIG. 4. With rising dopantconcentration, the reflection falls in the blue-green wavelength range(440 to 600 nm) and is maintained in the red range. Again, there isdependence on the dopant concentration, and the reflection in theblue-green region decreases ever further with rising dopantconcentration. This can also be seen visually in the substrates, theshade of which becomes ever darker and redder to the human eye withrising concentration.

7) A 200 nm-thick layer of the hole conductor HTM-014 (a triarylaminederivative from Merck) is deposited on an ITO electrode 20 by thermalvaporization (M2). A 150 nm-thick aluminum layer served as the counterelectrode 90. In three further experiments, the dopant K2 was doped intothe matrix material in concentrations of 5% (K2-5), 15% (K2-15) and 30%(K2-30) relative to the vaporization rate.

A component of size 4 mm² gives the respective current-voltagecharacteristics (IV characteristic) shown in FIG. 7. The component withconcentration 5% gave the characteristic labeled K2-5, the componentwith concentration 15% the characteristic marked K2-15, and thecomponent with concentration 30% the characteristic labeled K2-30.

For all concentrations, it is possible to show that the doping has aneffect on the IV characteristic. For all 3 concentrations, a rise in thecurrent densities within the range from −5 V to 1.5 V is found comparedto the reference component M2 composed of pure HTM014. In this context,it is additionally found that the doping effect is dependent on thedopant concentration and attains the highest current density atconcentration 15%. No ideal symmetric behavior of the characteristic isobserved, but an increase in the current density by a few orders ofmagnitude is achieved even in the negative voltage range, which showsthat injection of charge carriers from the aluminum cathode 90 is alsopossible.

The maximum current density does not increase compared to the referencecomponent (M2), but there is a reduction in voltage or increase incurrent density, particularly for small voltages in the range of 0 V to1V.

8) The materials produced in example 7 (M2, K2-5, K2-15 and K2-30) arecoated onto conductive substrates. These conductive substrates were usedto produce a total of 9 components of different dimensions. In this way,it is concluded, with regard to the determination of conductivity, thatthe effects measured are dependent on the thickness and size of thecomponents. For this substrate type, it is not necessary to apply analuminum counterelectrode.

The components thus produced give rise to the conductivity of the layerhaving the following specific values for the dopant concentrationsselected here:

K2-5: 3.45e−6 S/m

K2-15: 1.06e−6 S/m

K2-30: 1.45e−6 S/m

FIG. 8 shows the measured conductivities L in [S/m] against the dopantconcentration C in % by volume. The profile shows an improvement in theconductivity by one to two orders of magnitude. The maximum here is at aconcentration of 5% (K2-5), and the conductivities for 15% and 30%(K2-15 and K2-30) are very similar taking account of process andmeasurement variations and hence there is almost a constantconductivity. For a possible application, this gives rise to arelatively large processing window for the dopant concentration, withoutinfluencing the electrical conductivity thereof.

9) The layers produced in example 7 (M2, K2-5, K3-15 and K2-30) areadditionally each deposited on a quartz glass sheet. These samples donot have any electrical contacts and serve merely for measurement ofabsorption, emission and reflection spectra of the individual layers.For this purpose, in addition, a sample having the same thickness (200nm) of pure K2 (K2-100) was produced, in order also to determine theoptical data thereof.

The absorption spectra (FIG. 9, absorption A in [a.u.] against thewavelength λ in [nm]) show that there is a drop in the absoluteabsorption A at the absorption maximum at wavelength 380 nm. Theabsolute drop here for concentration 5% (K2-5) and 15% (K2-15) is atabout the same level, while the drop for dopant concentration 30%(K2-30) is greater. The pure 100% layer (K2-100) has a lowerconcentration again.

The absorption of the pure matrix material (M2) below 400 nm is thuslowered by the forming of the doped layer and the associated formationof a charge-transfer complex. At the same time, however, there is a risein the absorption A between 440 nm and 550 nm for the doped layers. Thislikewise shows the formation of a charge-transfer complex and successfuldoping. At the same time, it is additionally found that the rise inabsorption within this range increases with rising dopant concentration.The absorption spectrum therefore fits very well with the results of theconductivity measurements and of the IV characteristics from FIGS. 8 and7.

For the visible wavelength range from 400 to 700 nm, the absorption inthe blue to green wavelength range thus rises, as a result of which thelayers appear reddish to the human eye. The absorption of the pure K2layer (K2-100) is higher than the doped and undoped layers over theentire visible wavelength range.

The comparison of the photoluminescence spectra in FIG. 10, in which thenormalized emission E_(n) is plotted against the wavelength λ in [nm],of undoped matrix material (M2) and K2-doped matrix material shows thatthe emission at a wavelength of 432 nm customary for the matrix materialmoves to 406 to 408 nm for all doped layers. The basic emission profileis maintained, with a decrease in the absolute emission of HTM-014 whendoped with K2. In addition, a shoulder at 432 nm forms for all dopedlayers. The behavior of the K2-30 sample in the range of 480 to 700 nmis not a property of the material, but a measurement artefact caused bythe low overall emission of this sample. The absolute emissions of thelayers are not taken into account here; instead, each emission spectrumis normalized.

The pure K2 layer (K2-100) has its emission maximum at 423 nm with asecondary maximum at 485 nm.

The reflection spectra shown in FIG. 11 (reflection R against wavelengthλ in [nm]) likewise show the information already shown by the absorptionspectrum in FIG. 9. With rising dopant concentration, there is a drop inthe reflection in the blue-green wavelength range (400 to 580 nm), andit is maintained within the red range. Again, the dependence on thedopant concentration is present, and the reflection in the blue-greenregion decreases ever further with rising dopant concentration. This canalso be visualized in the substrates, the hue of which becomes everdarker to the human eye with rising concentration. It is likewiseconfirmed that the pure p-dopant layer (K2-100), for wavelengths below400 nm, has a lower absorption A and hence higher reflection R. Over theentire wavelength range and particularly in the range of 450 nm to 630nm, the reflection is much lower than that of the doped layers.

Examples 10) to 13) which follow show further working examples for thep-dopants:

10) A further example of a p-dopant which can be prepared by theabovementioned process from 3,5-difluorosalicylaldehyde andpentafluoroaniline is shown in its cis and trans forms in the formulaeVa and Vb:

11) Alternatively to pentafluoroaniline in example 13), it is alsopossible to use the tetrafluoroaniline derivatives2,3,4,5-tetrafluoroaniline, 2,3,4,6-tetrafluoroaniline or2,3,5,6-tetrafluoroaniline, or the tri-, di- or monofluoroanilinederivatives.

12) Further aniline derivatives which can be used in the abovementionedprocess are trifluoromethyl groups or derivatives additionally havingfluorine substituents, for example,2-fluoro-3-(tri-fluoromethyl)aniline,2-fluoro-4-(trifluoromethyl)-aniline, 2-fluoro-5-trifluoromethylaniline,2-fluoro-6-(trifluoromethyl)aniline,3-fluoro-2-(trifluoromethyl)-aniline,3-fluoro-4-(trifluoromethyl)aniline,3-fluoro-5-(trifluoromethyl)aniline,4-fluoro-2-(trifluoro-methyl)aniline,4-fluoro-3-(trifluoromethyl)aniline,5-fluoro-2-(trifluoromethyl)aniline.

13) The salicylaldehydes used for production of the p-dopant may also be4-(trifluoromethyl)salicylaldehyde or4-(trifluoromethoxy)salicylaldehyde.

The invention is not restricted by the description of the workingexamples; instead, the invention encompasses every novel feature andevery combination of features, which especially includes everycombination of features in the claims, even if this feature or thiscombination itself is not specified explicitly in the claims or workingexamples.

What is claimed is:
 1. An organic electronic component comprising: a substrate; a first electrode arranged on the substrate; at least one organic functional layer arranged on the first electrode, the at least one organic functional layer comprising a matrix material into which a p-dopant has been introduced; and a second electrode arranged on the at least one organic functional layer, wherein the p-dopant comprises a copper complex having at least one ligand, wherein the ligand has a benzene unit with two carbon atoms, wherein each carbon atom of the benzene unit has an aryloxy group and an iminium group directly attached as substituents, and wherein the at least one organic functional layer is hole-conducting.
 2. The component according to claim 1, wherein the aryloxy group and the iminium group of the ligand are a salicylaldiminate group.
 3. The component according to claim 1, wherein the copper complex contains a copper cation in an II oxidation state.
 4. The component according to claim 1, wherein the matrix material is a hole transport material comprising organic small molecules, polymers or mixtures thereof.
 5. The component according to claim 4, wherein the hole transport material is N, N′-di-[(1-naphthyl)-N,N′-diphenyl]-1,1′-biphenyl)-4,4′-diamine.
 6. The component according to claim 1, wherein molecule of the p-dopant is coordinated by at least one molecule of the matrix material.
 7. The component according to claim 1, wherein the p-dopant is present in the matrix material in a concentration of 0.1 to 50% by volume.
 8. The component according to claim 1, wherein the component is a field-effect transistor, a solar cell, a photodetector, an optoelectronic component, a light-emitting diode or a display.
 9. The component according to claim 1, wherein the functional layer is a hole transport layer and/or of a hole-conducting partial layer of a charge-generating layer sequence.
 10. A method for producing a p-dopant comprising a copper complex having at least one ligand, wherein the ligand has a benzene unit with two carbon atoms, and wherein each carbon atom of the benzene unit has an aryloxy group and an iminium group directly attached as substituents, the method comprising: synthesizing the at least one ligand so that, at the same time, a copper cation is complexed. 